Roll stabilizing system for an airborne device



Sept. 7, 1965 3,204,894

ROLL STABILIZING SYSTEM FOR AN AIRBORNE DEVICE N. D. S. G. GERTZELL 2 Sheets-Sheet l Filed June 25, 1965 A TTQRNEYS Sept- 7, 1965 N. D. s. G. GERTZELL 3,204,894

ROLL STABILIZING SYSTEM FOR AN AIRBORNE DEVICE Filed June 25, 1963 2 Sheets-Sheet 2 E/ i A E5 A v A v v 5j A A A E Ed A A A A F INVENTOR /v/Ls Av/p SVEN Gsm 6fm-ZELL United States Patent O 3,204,894 ROLL STAHJlZiNG SYSTEM FOR AN AIR'BGR'NE DEVICE Nils David Sven Gsta Gertzell, Bofor-s, Sweden, assigner to Aktiebolaget Bofors, lioiors, Sweden, a Swedish corporation Filed June 25, 1963, Ser. No. 290,524 Ciairns priority, application Sweden, June 29, 1962, 7,260/ 62 13 Claims. (Cl. 244-77) The present invention relates to airborne devices such as guided missiles, rockets, etc., and more particularly to devices of this kind which have at least one pair of guide members for horizontal guidance and at least one pair of guide members for vertical guidance.

The guide members used in connection with airborne devices of the kind referred to are, for instance, so-called spoilers which are mounted on the guide wings of the device. The yspoilers are usually in the form of flaps of an appropriate length and disposed at right angles to the -surfaces of the guide wings. Suitable spoilers are described for instance in German Patent 1,048,514. The aps are movable in the plane in which they are arranged, between two limit positions. They are set into said limit positions, for instance by a suitable electromagnetic control ldevice which in turn is controlled by a full wave signal of predetermined length. The full wave control signal which is used to control the spoilers is usually a :so-called pulse wave. The lengths of the two half-waves of the signal need not be equal and may be varied in length in reference to each other, provided only that the total length of the two halfwaves corresponds to the predetermined duration of the full wave. As a result the flap of each spoiler may be retained in either limit position for predetermined but varying periods of time. When no guidance is imparted to the airborne device, the periods of time in which spoilers remain in the limit positions will be equal.

The full wave control signals used for controlling the electromagnetic control device may be fed to the airborne device by radiation waves sent from a transmitter on the ground, or by wire conductors.

If the airborne device is a rocket, the guide members are in the form of deflecting means for guiding the ow of the gases emanating from the rocket. Such deflecting means correspond in function to the afore-referred to spoilers.

In some cases it is desirable to impart to airborne devices of the general kind above referred, a spin about the longitudinal axis of the device, but in other cases such an axial spin or rotation is undesirable. It has been proposed to provide in the airborne device specific means for eliminating an undesirable spin or rotation, often referred to as roll movement. Such anti-roll means may comprise a gyro which is mounted in the device and supplies information as to whether the device spins about its longitudinal axis. Stabilizing means of this kind as heretofore known, are complex and require considerable space.

It is a broad object of the present invention to provide stabilizing means for compensating any roll tendency of the device by means of the already existing guide members of the device.

According to the invention the aforementioned control signal which is used to control the guide members, is passed through an adder before itis fed t the guide members. The same signal is also fed to a circuit means which is responsive to a departure of the airborne device from a state of equilibrium in respect to its longitudinal axis and which varies the signal fed to it in accordance with such changes of the device from its state of equilibrium. The supplementary or corrective signal thus obtained is ICC then fed to the adder. Accordingly, the guide members of the airborne device will be controlled by the initial control signal and also by the corrective signal which is a function of a rotary deviation of the device in respect to its desired state of equilibrium. The circuitry is so arranged that the corrective signal is added to the original control signal which is fed to one of the guide members of a pair of guide members and is subtracted from the original signal which is fed to the other guide member of the same pair.

In most instances it has been found to be adequate to supply the corrective signal only either to the guide members for lateral or forvertical deflection, but the corrective signal may also be fed to the guide members for both lateral and vertical deflection.

A signal which is indicative of the angular deviation of the airborne device in reference to the longitudinal axis of the device may be obtained by means of the transition point in a full wave pulse signal. This point is caused to occur at a predetermined time when there is no deviation and the departure of the occurrence of the transition point from such predetermined time then constitutes a measure of the angular deviation of the airborne device.

The corrective signal may either be in phase with the original command or control signal, or the phase of the corrective signal may be displaced by a half-cycle in relation to the command or control signal. In any event, the corrective signal should be so arranged that it utilizes only the leading and the trailing part of each full wave. If the phase of the corrective signal is not displaced in relation to the control or command signal, it is advisable to use for instance the first part of a signal cycle for roll stabilization. The transition point for the corrective signal should then be within such first part and the remainder of the cycle is utilized for control information. Accordingly, the transition point for the control or command signal must be within the remaining part of the cycle. In the event the phase of the corrective signal is not displaced by a half cycle in respect to the control signal, the transition point may be caused to occur at any desired moment.

The use of la corrective signal which is displaced in phase may cause distortion phenomena when such signal is subsequently added to the control signal. To avoid such distortions, the invention provides for the use of limit means which give preference either to the corrective signal or the control signal or cause that both signals obtain the same preference when added.

Other and further objects, features and advantages of the invention will be pointed out hereinafter and set forth in the appended claims constituting part of the application.

In the accompanying drawing a preferred embodiment of the invention is shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is a typical circuit diagram of a roll stabilizing system according to the invention for use with an airborne device, and

FIG. 2 shows twelve graphs of signal conditions occurring in the system.

Referring now to the iigures in detail, the circuit diagram according to FIG. 1 comprises a transmitter l which generates a square pulse signal as shown in graph A of FIG. 2. The signal has a predetermined length T and a variable transition point. Two conductors 2 and 3 are connected to the transmitter and the signal designated by El can be divided so that there is a potential Ea between conductor 2 and ground and a potential Ea' between conductor 3 and ground. The characteristic of signal Ea is shown by graph B of FIG. 2 and the characteristic of signal Ear is shown by graph C in FIG. 2. The transmitter 1 may be visualized as being a ground station and conductors 2 and 3 may be wires for supplying current to a device 1A while in iight.

The signal E,u between conductor 2 and ground is first fed through a resistor 4 and a conductor 5 to a multivibrator 6 of conventional design and then by means of a conductor 7 to a coil 8 which whenl energized attracts an armature 9 coupled to a spoiler blade 10 rotatbly mounted on a support member 11. A spring 12 biases the spoiler blade into the dotted line position when coil 8 is deenergized.

Signal Ea' is similarly transmitted to a multivibrator 15 via a resistor 13 and a wire 14. From the multivibrator the signal is transmitted via a conductor 16 to a coil 17 which attracts its armature 18 when energized. The armature is coupled to a spoiler blade 19 movably supported on a support member 20 and biased into the dotted position by a spring 21 when coil 17 is de-ene'rgized.

In the diagram of FIG. 1 it is assumed that coils 8 and 17 are energized so that the spoiler blades are in the full line position.

Signal Ea' is further transmitted by a conductor 22 to a derivatin'g network 23 in which the signal is so shaped that it has the shape shown in graph D. The modulated signal is designated Eb and is transmitted from network 23 to a rectifier 25 in which it obtains the shape shown in graph E. The further modified signal, designated by EC, is transmitted by a conductor 26 to a multivibrator 27 in which the signal is time-displaced by a half cycle. The signal now obtains the shape shown in graph F and is designated by Ed. The signal Ed is transmitted by conductor 28 to a unit 30 including a sawtooth generator connected in series with a multivibrator. The signal is further transmitted by a conductor 29 to a .second unit 31 of the same kind as the unit 30. A roll-'responsive potentiometer 32 is suitably connected to a gyro 50 mounted in the airborne device 1A. The end terminals of the potentiometer are connected by conductors 36 and 37 to a stabilizing network 35 and also to a source of direct current. The movable contact 33 of the potentiometer is connected to the stabilizing network and the D C. source. As it is diagrammatically indicated in FIG. l, the position of contact 33 is controlled by the gyro in a conventional manner. p

If there is no roll deviation, the contact member 33 is in its inactive or rest position, that is in the midpoint position of the potentiometer. In the event a roll deviation occurs, the stabilizing network Will transmit a voltage -l-Ee through conductor 39 to the unit 30 and a voltage -Ee through the conduct-or 38 to the unit 31. In the unit 30 the signal Ed actuates the sawtooth generator in the manner indicated by graphY G. The sawtooth voltage is designated by Ef. In addition, unit 30 will generate a pulse signal Eh as shown in graph H but only when the value of signal Ef has a value corresponding to Ee. The pulse signal Eh can be taken out through a terminal 40. Furthermore, due to the use of a multivibrator an inverted image signal of signal Eh is obtained at a terminal 41. The inverted signal is designated by EH' and is shown by graph I.

It is advisable to provide a fixed basic voltage to which the signal Ee is added. The pulse signal is released only when there is a voltage corresponding to the sum total of the basic voltage and signal Ee. In this manner a fixed reference point for signal Eh is obtained.

Unit 31 functions in the same manner as unit 30. A fixed basic voltage is also provided to which signal --Ee is added. The sawtooth generator of unit 31 generates a signal Eg shown in graph I. The signals supplied by units 31 may be taken out at terminals 42 and 43. The signals are designated by Ei and Ei and are shown by graphs K and L respectively.

As it is now apparent, corrective signals indicative of the angular deviation of the airborne device in reference to its longitudinal axis are obtained at the terminals of units 30 and 31. Theoretically, it would be suiicient to obtain one signal from each of these units and to feed such signals to coils 8 and 17 respectively, but mathematical calculations show that when a dominance of the control or command signal by the roll indicative signal is desired, such dominance being advantageous to obtain `the correct value of the signals to be fed to coils 8 and 17 respectively, three signals should be added, namely for the coil S, signals Ea, Eh and Ei and for coil 17 the signals En, Eh and Ei. Signal Eh is transmitted from terminal 41 through conductor 44 to a resistor 45 and also to a resistor 46. Signal E1 is transmitted from terminal 42 through a conductor 47 to a resistor 48 and also to a lresistor 49. Accordingly, conductor 5 will carry the sum total of signals Ea, Eh and E, and conductor 14 will carry the sum total of signals Ea, Eh and Ei. Both multivibrators 6 and 1 5 are so arranged that they will pass only a signal which consists of the sum of at least two part signals, that is a passed signal must include signals simultaneously from at least two of the resistors 4, 45 and 48, or 13, 46 and 49 respectively.

As it is evident, signals Ea and En can be combined in some other way from the signals obtained from units 30 and 31 when it is desired to give the control or command signal preference over the roll stabilizing signals, or when it is desired to give the command signals and the stabilizing signals equal standing. A person skilled in the art will be readily able to select the required combinations in accordance with well understood mathematical rules.

As has been pointed out before, a phase displacement of signal Ec may be omitted. In such event multivibrator 27 may be dispensed with and transmitter 1 may be equipped with control devices arranged in a manner such that a possible transition in the command or control signal occurs within a selected part of the cycle. The same applies to units 30 and 31 where the transition must also take place within the remaining part of the cycle. In such an arrangement resistors 46 and 48 may be omitted, as can be readily shown by mathematical calculations. The sum total of signals Ea and Eh is then fed to coil 8 and the sum total of signals Ea and E, is fed to coil 17. Otherwise the modified system functions as previously described in detail.

While the invention has been described in detail with respect to certain now preferred examples and embodiments of the invention, it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and 'modications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A roll stabilizing system for an airborne device subject to roll movements when in flight and having at least one pair of electrically controllable guide members for horizontal guidance and at least one pair of electrically controllable guide members for vertical guidance of the device, each guide member of both pairs being mounted pivotal between two limit positions, said system 4comprising circuit means for generating a full wave pulse signal having a variable transition point and feeding said signal to the guide members of at least one of said pairs `to control the position of the respective guide members,

monitoring circuit means for varying the transition point of the full wave control signal corresponding to a departure of the device from a spatial reference attitude to obtain a corrective signal, circuit means for feeding said full wave pulse signal to said guide members for control thereof, and circuit means for feeding said corrective signal additively to one of the guide members of the respective pair and subtractively to the other guide member of said pair whereby the guide members of the respective pair are position controlled by a composite signal composed `of said control signals and said corrective signal.

2. A roll stabilizing system according to claim 1 and comprising means for displacing the corrective signal in phase.

3. A roll stabilizing system according to claim 2 wherein said corrective signal is displaced by one half cycle.

4. A roll stabilizing system according to claim 1 wherein the circuit means for generating said full wave pulse signal are connected to the guide members of the respective pair so that one positive half wave is fed to each of said guide members.

5. A roll stabilizing system according to claim 1 wherein said monitoring circuit means generate two corrective signals, each corresponding to the spatial attitude of the device, and wherein said circuit means for 'feeding the corrective signals to the guide members combine both corrective signals with the control signals to composite signals fed to the guide members.

6. A roll stabilizing system according to claim 5 and comprising circuit means for generating inverted image signals f said composite signals and adding said inverted signals to the composite signal fed to one of said guide members.

7. A roll stabilizing system according to claim and comprising circuit means for generating inverted image signals of said composite signals and adding said inverted signals to the composite signals fed to the other of said guide members.

8. A roll stabilizing system according to claim 5 and comprising limiting circuit means for each of said guide members, each of said limiting circuit means passing only composite signals composed of at least two signals.

9. A roll stabilizing system according to claim 5 and comprising circuit means for generating inverted image signals, one of the composite signals and the inverted image signal of the other composite signal being added to one of the half Waves of the full wave signal and the inverted image signal of said one composite signal and said other composite signal being added to the other half wave.

10. A roll stabilizing system according to claim 5 and comprising circuit means for generating inverted image signals .of said composite signals, the inverted image signal of one of the composite signals being added to one of the half waves of the full wave signal.

11. A roll stabilizing system according to claim 10 and comprising limiting circuit means for each of said guide members, each of said limiting means passing only inverted image signals composed of at least two inverted image signals.

12. A roll stabilizing system according to claim 5 and comprising circuit means generating inverted image signals of said composite signals, one of the composite signals being added to one of the half Waves.

13. A roll stabilizing system according to claim 12 and comprising limiting circuit means for each of said guide members, each of said limiting circuit means passing only composite signals composed of at least two of the aforesaid signals.

References Cited by the Examiner UNITED STATES PATENTS 1,879,187 9/ 32 Goddard M11-52 2,644,397 7/ 53 Katz 102-50 3,064,930 11/ 62 Chevalier 244-90 X 3,082,979 3/ 63 Hendrick 244-76 MllTON BUCHLER, Primary Examiner.

RALPH D. BLAKESLEE, Examiner. 

1. A ROLL STABILIZING SYSTEM FOR AN AIRBORNE DEVICE SUBJECT TO ROLL MOVEMENTS WHEN IN FLIGHT AND HAVING AT LEAST ONE PAIR OF ELECTRICALLY CONTROLLABLE GUIDE MEMBERS FOR HORIZONTAL GUIDANCE AND AT LEAST ONE PAIR OF ELECTRICALLY CONTROLLABLE GUIDE MEMBERS FOR VERTICAL GUIDANCE OF THE DEVIDE, EACH GUIDE MEMBER OF BOTH PAIRS BEING MOUNTED PIVOTAL BETWEEN TWO LIMIT POSITIONS, SAID SYSTEM COMPRISING CIRCUIT MEANS FOR GENERATING A FULL WAVE PULSE SIGNAL HAVING A VARIABLE TRANSITION POINT AND FEEDING SAID SIGNAL TO THE GUIDE MEMBERS OF AT LEAST ONE OF SAID PAIRS TO CONTROL THE POSITION OF THE RESPECTIVE GUIDE MEMBERS, MONITORING CIRCUIT MEANS FOR VARYING THE TRANSITION POINT OF THE FULL WAVE CONTROL SIGNAL CORRESPONDING TO A DEPARTURE OF THE DEVICE FROM A SPATIAL REFERENCE ATTITUDE TO OBTAIN A CORRECTIVE SIGNAL, CIRCUIT MEANS FOR FEEDING SAID FULL WAVE PULSE SIGNAL TO SAID GUIDE MEMBERS FOR CONTROL THEREOF, AND CIRCUIT MEANS FOR FEEDING SAID CORRECTIVE SIGNAL ADDITIVELY TO ONE OF THE GUIDE MEMBERS OF THE RESPECTIVE PAIR AND SUBTRACTIVELY TO THE OTHER GUIDE MEMBER OF SAID PAIR WHEREBY THE GUIDE MEMBERS OF THE RESPECTIVE PAIR ARE POSITION CONTROLLED BY A COMPOSITE SIGNAL COMPOSED OF SAID CONTROL SIGNALS AND SAID CORRECTIVE SIGNAL. 